The toposheet figure is 47 H/8 and 47 H/12. From malvan bay a concatenation of submerged and exposed bouldery islands extend towards south. In this concatenation there are several islands and other little islets around sindudhurg garrison are mandle stones, malvan stones etc. sindhudurg garrison is situated around north tip.
Wilkinson ( 1871 ) gave a brief history on study of the geological construction of southern Konkan. Iyer ( 1939 ) gave a generalised history of the geology and construction of the country. some mentions to the geology and construction of this country are available in the advancement studies of Hemmady l960 ) , Konala 1963 ) , Suryanarayana ( 1965 ) etc.
The Rivers run outing in these countries originate from sahyadris with distance of 20-30 kilometer. The drainage observed is dendritic, they run directly and seldom meanders. No deltas are found along the seashore may be due to little drainage basin, low sedimentary supply and estuarial conditions of river. Achra and gallivant river drainage form is controlled by tectonic quality. 4
The geomorphic units of the country are classified into three classs On the footing of their signifier, generation and geomorphic procedures.
Unit of measurements of Marine beginning are: beach littorals, stabilized suits with sand dunes, beach ridges, and wave cut benches and platform.
Unit of measurements of fluvial origin the clay flats and alluvial sediment, channel bars and point bars, and fen and mangrove countries represent the present inundation field.
Unit of measurement of stripping the alluvial patios and higher vale fills represent the older inundation field. The cleft coastal highland with stray hills has been considered as a beginning.
The different litho units exposed in the country, in general tendency NW-SE to E-W.
The constructions noticed in the country are normally of two types viz
( a ) No tectonic construction
( B ) Tectonic construction.
No tectonic construction
Bedding plane is represented in the signifier of composing and color sets as is noticed in Asrondi quartzite, BHC, staurolite- schist and carbonous stone near Ramgarh.
Tectonic or secondary constructions include leafing, outline creases, shear zones/faults and articulations.
The country mapped, is covered by thick screen of laterite and dirt and so it is hard to construe the construction, as ideal exposures for the measurings of attitudes are rare. The undermentioned observations, nevertheless, have been recorded from a few scattered outcrops exposed in vale and good subdivisions. 5
The leafing tendency of the Archaean stones, is approximately NW-SE with steep dips runing from 75 & A ; deg ; to 80 & A ; deg ; , largely to the West conforming to the Dharwarian work stoppage tendency except for a few quartzite outcrops at topographic points near Malvan, which are about perpendicular.
Narrow additive strips of beach littorals with width changing from 30 to 300 meters are seen developed along the seashore chiefly restricted to the emblements and estuary oral cavity. This unit is characterised by really light tones and all right texture and is devoid of flora. A twine of additive partially submerged off shore sand bars are observed near the about consecutive shoreline between Achra and Kalavale carbon blacks.
The extended outcrops of Meta quartzite are observed within the recent beach littorals. Along the seashore of malvan and nivti good developed closed separated breaks and slicken side ‘s surface within the pudding stones and quartzite ‘s are non common. These oligomict pudding stones and quartzite ‘s exhibits good developed primary sedimentary constructions such as medium graduated table cuneus and trough cross bedclothes, sub-horizontal field bedclothes, hummocky bedclothes, wavy cross lamination, trochoidal rippling lamination etc.
Extensive outcrops of orthoquartzite and shales are curious to the west border of the country.
A wide coastal plane of about 2 kilometers width and about 5 kilometers length is developed between malvan and karli.on this coastal plane 3 to 4 beach sand dunes ridges jumping with tidal level clays are easy distinguished on aerial exposure, as on beach sand dune ridges heavy coconut plantation and low lying tidal level clays entirely paddy Fieldss are present. 6
To the North of malvan the most dramatic characteristic of the beach is the littoral concrete or beach stone, which continues over long stretch. This littoral concrete occurs as a bouldery beach either straight attached to the mainland or separated by sandy or boggy countries. The bouldery beach gives protection to the seashore against strong moving ridges. These stones are exposed merely when sea recedes. They have some general composing like the loose beach sand. Its crumbly to good cemented stone consisting of mineral grains, fragments, calcerious dust which are cemented by CaCO3. happening of beach stone in inter tidal zone every bit good as 2-4mts above present twenty-four hours high H2O line may possibly bespeak minor fluctuations of sea degree.
Beach Ridges and Dunes
They are the sets of really low sandy ridges which are parallel roughtly to present shoreline. Tthese represent continous retreat of the sea along the seashore, hence each was one time a shoreline in itself.
Recent dunes really light tone in air photes and shows rise of 10-15 kilometer islands. These dunes are stabalised by heavy growing of thick flora. Resent dunes in the country are cut by wave action bespeaking that it is now depositional in nature.
Pirwadi talashil country is a sand saloon represented by narrow submergent coastal fields ; they besides have sand bars located at oral cavity of river Gad. The river got beaches on its offshore side bound and tapering terminal on river side.and are oblique on the sea side this indicates waver are of import agent in maintaining the recess unfastened. Wave behaviours in this country is west – south – West dominant and west North West subordinate. On the coastal sand bars heavy coconut plantation is chiefly observed.
Feldspathic gneiss has good developed mesoscopic creases exhibit assorted forms. Whereas kudal kankavli and vengurla archaean stones are tightly folded in assortments of anticline and syncline. 7
It ha been recagonized that the country has undergone three stages of turn uping. This was evidenced from the little graduated table constructions within the stone types in and along the country under consideration. The three coevalss of creases that are recagoined are:
They are one which are tight isoclinic, their axial plane swerving along NE-SW and seldom NW-SE, with steep dip towards west. They are good preserved in BHQ set exposed near Ashiye. At topographic point their axial hint tendencies North West-South East.
The 2nd stage of distortion has resulted F2 creases, these are tight to open ( asymmetrical ) and at times reclined in nature. Their axial planes trends North-South to North West-South East and dips reasonably towards E.
They by and large are soft to open deflection, their axial plane tendencies NNE-SSW to North East-South West and dips reasonably towards E. F3 creases are developed on the limbs of F2 crease.
Three major creases have been noticed near Gothane, South of Oros
Budrukh and Asrondi, whose axes tendency North West -South East. The mineral gatherings of pelitic/semipelitic stones reveal that they have suffered almandine-amphibolite facies of metamorphism, whereas extremist basic/ basic stones have undergone green schist facies of metamorphism.
Eye creases intervention of F1 and F2. Folds have given rise to development of oculus creases in Pisekamte quartzite. Their long diagonal defines the F1 crease and short diagonal represents the F2 crease
Sudden difference in lift of archean and deccan lava flows is declarative of blaming. Galavadi has been faulted between kaladgi and deccan lava flows lava flows exhibiting horizontal and perpendicular articulations in all waies. 8
In general, spacing of articulations in flinty gneisses is more. At topographic points, articulations are filled by secondary silicon oxide and epidote.
Along the country there are copiousness of drops. These are active drops, active due to present marine procedure. Here the rate of arrested development of clifed seashore varies with lift, stone opposition, geological constructions and instant moving ridge energy. Under this country retreat of drops are pronounced. Due to direct onslaught of moving ridges, big clefts are developed in laterites. Fall of sea degree might go forth old beach scratch platform with derelict drops.
Wave cut platforms
These are by and large seen along the cliffed seashore of the country. All along the country the drops and promontories are bordered by moving ridge cut platforms. These platforms have soft inclines. Some show thin veneer of alluvial sediment, these patios are distinguishable arrested development of sea degree along the seashore.
Rocky islands are the stray outcrops. By and large situated 1-2Km off shore upper limit by far in 6-8 kilometer. they represent degage parts of coastal promontory that are now isolated from the seashore. Some islands are connected to tag land by alluvial sedimentations.
Island arch ‘s
These units are restricted to contract belt runing 200m broad along the coast.55 % of Indian seashore is beach fringed, constantly sandy, gently gradient. These are by and large assossiated with flaxen beaches found at the bay caputs along consecutive shores on the offshore side of the sand bars. 9
These are the common phenomenon seen in the coastal country under survey. They are by and large seen along the sea drops where there is stick outing portion of the drop gets detached from the chief mass and falls away, this happens due to clasing of the moving ridges along the surface of these cliffs.In this instance the mass below the drop starts gnawing and easy after a span of clip the mass topples down into the sea.
This is sort of similar phenomenon seen along the malvan seashore but the difference here is that the mass due to floging of the moving ridges on the wall of drop clefts are originated from the top, this mass so slips and falls off.
Therefore topple and faux pass are the two associated constructions seen along the seashore. Where the flora is screens over the fallen land mass its toppling and if the flora is deceasing it ‘s a faux pas. 10